CONVERT OPUS → FLAC (OPUS to FLAC)
Fast, secure OPUS to FLAC conversion. No registration required.
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HOW TO CONVERT OPUS → FLAC
Upload the OPUS
Drop or select your OPUS file. The upload is encrypted and the file is queued for conversion.
Transcode via FFmpeg
FFmpeg decodes the OPUS stream to PCM internally, then re-encodes as FLAC at the bitrate you select.
Download the FLAC
The FLAC is delivered as a direct download; metadata and cover art transfer automatically where possible.
Opus is a lossy codec defined by RFC 6716, built on SILK and CELT hybrid coding and delivered inside Ogg or WebM containers. It encodes audio by discarding psychoacoustically masked frequencies, meaning every Opus file already contains permanent spectral loss relative to the original PCM source. Converting Opus to FLAC produces a losslessly compressed file, but that lossless compression operates on whatever decoded PCM survives after Opus decoding — not on the original recording. The result is a bit-for-bit stable FLAC that faithfully represents the Opus output, yet it cannot reconstruct frequencies the encoder discarded. The typical driver for this conversion is toolchain compatibility: editing software, archival pipelines, hardware players, and broadcast tools that accept FLAC but not Ogg Opus. FLAC stores audio as 16-bit or 24-bit integer PCM inside a streamable container with full Vorbis-comment metadata and optional MD5 checksums per frame, making it the preferred interchange format when a downstream tool needs a lossless container without caring whether the source was originally lossless.
Why convert OPUS to FLAC
The most concrete reason to do this conversion is player and DAW compatibility. Ogg Opus has limited native support in hardware players, certain versions of Pro Tools, and older broadcast playout systems that have never shipped an Opus decoder. FLAC enjoys near-universal support across Linux, macOS, Windows, Android, iOS, and essentially all professional audio software. A secondary reason is archival policy: some institutional and broadcast archives require a lossless container format on intake, accepting FLAC but rejecting Opus regardless of its perceptual quality. The conversion satisfies the policy constraint while preserving every bit of audio information that Opus retained at encode time.
OPUS vs FLAC — Technical specifications
Side-by-side comparison of the technical details.
OPUS
- MIME type
- audio/opus
- Extensions
- .opus, .ogg (container)
- Standard
- RFC 6716 (2012)
- Sample rates
- 8, 12, 16, 24, 48 kHz
- Latency
- 5-60 ms (configurable)
- MIME Type
- audio/opus
- Extension
- .opus
- Category
- Audio Files
- Full Name
- Opus Audio
- Conversion Engine
- FFMPEG
FLAC
- MIME type
- audio/flac
- Standard
- Open-source reference implementation (Xiph.Org)
- MIME Type
- audio/flac
- Extension
- .flac
- Category
- Audio Files
- Full Name
- FLAC Audio
- Conversion Engine
- FFMPEG
- Max bit depth
- 32 bits per sample
- Max sample rate
- 655 350 Hz
- Max channels
- 8
| Specification | OPUS | FLAC |
|---|---|---|
| MIME type | audio/opus | audio/flac |
| Extensions | .opus, .ogg (container) | — |
| Standard | RFC 6716 (2012) | Open-source reference implementation (Xiph.Org) |
| Sample rates | 8, 12, 16, 24, 48 kHz | — |
| Latency | 5-60 ms (configurable) | — |
| MIME Type | audio/opus | audio/flac |
| Extension | .opus | .flac |
| Category | Audio Files | Audio Files |
| Full Name | Opus Audio | FLAC Audio |
| Conversion Engine | FFMPEG | FFMPEG |
| Max bit depth | — | 32 bits per sample |
| Max sample rate | — | 655 350 Hz |
| Max channels | — | 8 |
OPUS vs FLAC — Strengths and limitations
What each format does best, and where it falls short.
OPUS Strengths
- Best-in-class quality across the entire bitrate range.
- Royalty-free and patent-free.
- Ultra-low latency — suitable for live voice and music.
- Handles speech and music equally well — no need to switch codecs.
- Mandatory codec in WebRTC, so supported in every browser by design.
Limitations
- Very low hardware decoder adoption — software-only on most phones.
- Older platforms (legacy Windows apps, old cars) may not play .opus files.
- Container semantics confusing — Opus lives inside Ogg, WebM, or MP4.
FLAC Strengths
- Lossless — decoded audio is bit-exact identical to the source.
- 40-60% smaller than uncompressed WAV/AIFF.
- Free, patent-free, open-source reference implementation.
- Built-in error detection via MD5 checksums.
- Streaming-friendly — seek tables let you jump to any timestamp instantly.
Limitations
- File sizes still large compared to lossy codecs (5-10× bigger than AAC for same audio).
- Not suitable for low-bandwidth scenarios like streaming on mobile data.
- Older MP3 players and car stereos may not decode FLAC.
Quality & Compatibility
Opus decodes to 32-bit float PCM internally; the decoder then dithers or truncates to the target bit depth, typically 16-bit integer for standard stereo streams or 24-bit if the source was encoded at high bitrate from a 24-bit master. FLAC captures that PCM exactly — its Rice-coded compression is mathematically lossless, so the FLAC file is a transparent container around the decoded output. What is permanently absent is whatever the Opus encoder removed: typically high-frequency content above roughly 20 kHz on 320 kbps streams (Opus bandwidth is capped at 20 kHz in fullband mode), pre-echo artifacts at transients on lower bitrates, and any spatial information beyond stereo unless the source used Opus multistream. Vorbis comments from the Opus file — TITLE, ARTIST, ALBUM, TRACKNUMBER, DATE — map cleanly to FLAC Vorbis comments. ReplayGain tags written as R128_TRACK_GAIN or R128_ALBUM_GAIN in Opus do not have a direct FLAC equivalent and should be recalculated or manually remapped to REPLAYGAIN_TRACK_GAIN after conversion. Channel alpha does not apply to audio.
Tips for Best Results
- Feed the converter the highest-bitrate Opus file available — 160 kbps stereo or above — because FLAC freezes whatever spectral content the Opus decoder outputs, and a higher-bitrate source preserves more of the audible band before any conversion happens.
- After downloading the FLAC, verify the sample rate matches your expectation: Opus internally normalizes all audio to 48 kHz, so the output FLAC will be 48 kHz even if the original recording was 44.1 kHz — resample deliberately in your DAW if your target pipeline requires 44.1 kHz.
- Check and rewrite ReplayGain tags manually or with a tool like fre:ac after conversion, because the Opus R128_TRACK_GAIN value uses a different reference level (EBU R128, -23 LUFS) than the ReplayGain 2.0 convention expected by most FLAC-aware players, and an unconverted tag will cause incorrect loudness normalization.
Frequently Asked Questions
Lossy-to-lossy conversions (most combinations) re-compress the audio, which technically introduces some loss. At a 192 kbps or higher target it is inaudible on normal equipment. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy transcodes are only as good as the target bitrate you choose.
For voice content (podcasts, audiobooks, lectures) 128 kbps is indistinguishable from higher bitrates. For music, 192-256 kbps covers most listening; 320 kbps is the ceiling for FLAC and the right choice for audio you plan to edit further. Above that, prefer a lossless target instead.
Yes. Title, artist, album, year and cover art travel from the OPUS container to the FLAC container automatically where both formats support them. If a tag field has no FLAC equivalent, it is dropped silently. Use any tag editor (Mp3tag, MusicBrainz Picard) to fine-tune afterwards.
Opus Audio
Source formatOpus is a versatile, open-source audio codec optimized for both speech and music at very low bitrates. It is the standard for WebRTC voice calls and excels at real-time communication.
FLAC Audio
Target formatFLAC is an open-source lossless audio codec that compresses audio to roughly 50-60% of its original size without any quality loss. It is the preferred format for audiophiles and music archival.
Going the other way? Convert FLAC back to OPUS with the same engine.
Common Use Cases
Share across platforms
Send FLAC files to anyone without worrying about whether they have the right software for OPUS.
Embed in documents
Drop FLAC output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
FLAC often produces smaller files than OPUS for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
OPUS vs FLAC — Typical file sizes
Approximate file sizes for common scenarios.
- Voice call (24 kbps) 180 KB/min
- Podcast (48 kbps) 21 MB/hour
- Music (128 kbps) ~1 MB/min
- 3-min song (CD quality) 20-30 MB
- Full album (10 tracks, CD) 250-400 MB
- 3-min song (hi-res 24-bit/96 kHz) 80-120 MB
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Related comparisons
See these formats side by side to understand which fits your use case best.
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